In recent years, as a technique of supporting safe driving of automobiles, various techniques of displaying images of areas which are difficult to see by drivers and images of blind areas for the drivers have been proposed. In particular, since eyesight on right and left sides of vehicles is considerably narrow at T-junctions, such a supporting technique is particularly important. As the supporting technique, the following technique has been disclosed. That is, a plurality of cameras are disposed on a front end of a vehicle to capture images of right and left regions, and the images captured by the cameras are displayed in a display unit such as a car-mounted monitor. Furthermore, a technique for realizing early detection of an object, such as another vehicle or a pedestrian, which is approaching the own vehicle has also been proposed. For example, Japanese Laid-open Patent Publication No. 2005-276056 discusses a technique of capturing a plurality of images in a time series manner, extracting feature points from the images, comparing the feature points of the images with each other, associating feature points which have a high degree of correlation with each other, calculating optical flows, and detecting an approaching object. Note that such an approaching object detection function is included in a general navigation function. That is, one display unit has the approaching object detection function and the navigation function.